boost/type_erasure/concept_interface.hpp

0001 // Boost.TypeErasure library
0002 //
0003 // Copyright 2011 Steven Watanabe
0004 //
0005 // Distributed under the Boost Software License Version 1.0. (See
0006 // accompanying file LICENSE_1_0.txt or copy at
0007 // http://www.boost.org/LICENSE_1_0.txt)
0008 //
0009 // $Id$
0010
0011 #ifndef BOOST_TYPE_ERASURE_CONCEPT_INTERFACE_HPP_INCLUDED
0012 #define BOOST_TYPE_ERASURE_CONCEPT_INTERFACE_HPP_INCLUDED
0013
0014 namespace boost {
0015 namespace type_erasure {
0016
0017 /**
0018  * The @ref concept_interface class can be specialized to
0019  * add behavior to an @ref any.  An @ref any inherits from
0020  * all the relevant specializations of @ref concept_interface.
0021  *
0022  * @ref concept_interface can be specialized for either
0023  * primitive or composite concepts.  If a concept @c C1
0024  * contains another concept @c C2, then the library guarantees
0025  * that the specialization of @ref concept_interface for
0026  * @c C2 is a base class of the specialization for @c C1.
0027  * This means that @c C1 can safely override members of @c C2.
0028  *
0029  * @ref concept_interface may only be specialized for user-defined
0030  * concepts.  The library owns the specializations of its own
0031  * built in concepts.
0032  *
0033  * \tparam Concept The concept that we're specializing
0034  *         @ref concept_interface for.  One of its
0035  *         placeholders should be @c ID.
0036  * \tparam Base The base of this class.  Specializations of @ref
0037  *         concept_interface must inherit publicly from this type.
0038  * \tparam ID The placeholder representing this type.
0039  * \tparam Enable A dummy parameter that can be used for SFINAE.
0040  *
0041  * The metafunctions @ref derived, @ref rebind_any, and @ref as_param
0042  * (which can be applied to @c Base) are useful for determining the
0043  * argument and return types of functions defined in @ref concept_interface.
0044  *
0045  * For dispatching the function use \call.
0046  */
0047 template<class Concept, class Base, class ID, class Enable = void>
0048 struct concept_interface : Base {};
0049
0050 }
0051 }
0052
0053 #endif